The present invention relates generally to animal watering devices and more particularly to a means for preventing such animal watering devices from freezing in cold weather.
Automatic watering devices for allowing animals to drink therefrom whenever desired have been in use for many years. One of the traditional problems with the use of such devices has been to keep them from freezing in cold weather. This problem has, of course, been solved in many ways, but many of these solutions are unacceptable because too much energy is required in order to keep such devices working properly. Various thermostatically controlled electrical heating elements have been used, but whenever a thermostat is added to the circuitry, this involves an additional expense for such an element and also tends to decrease the reliability because of the possible failure of such thermostatic element. Accordingly, it has been determined that the use of a very low wattage heating element which runs continuously can in some cases be far more economical and more reliable than many designs which use thermostatically controlled heating elements. One design for such a watering device using a low wattage heating element on a continuous basis in cold weather is disclosed in U.S. Pat. No. 4,069,409 to Noland.
It has been determined, however, that there is one disadvantage of such a watering device having a heating element continually supplying heat to an insulated housing, and that is that if there are not enough animals to continuously use the waterer, it is possible that there can be a buildup of heat around the nipple valve from which the animals drink, thereby causing the water to be so warm that the animals are reluctant to drink therefrom.
One solution to this problem has been to reduce the amount of heat applied to the waterer, but it has been found that in certain cases other parts of the watering device may freeze unless a certain minimum amount of heat is supplied. Therefore, there is a need for a way to distribute the heat supplied so that a buildup of heat does not occur at the nipple valve.